The invention relates to an apparatus for mixing the vapor and liquid phases of anhydrous ammonia, to obtain a homogeneous, vapor-liquid mixture of the ammonia, which can be applied uniformly to soil, feed grains, silage, and the like.
A common use for anhydrous ammonia is to apply it to the soil as a nitrogen fertilizer. Conventional field applicators for applying the ammonia usually include a storage tank, a meter regulator, a flow equalizer manifold having a fixed or variable orifice, and a row of knives which are pulled through the soil at a depth of several inches. In a typical field application, the ammonia is stored in the tank at about 100-200 psig at ambient temperature. As the ammonia is metered through the regulator and into the flow equalizer manifold, the pressure drops to about 5-30 psig. Because ammonia has a relatively high vapor pressure, and because it enters the manifold at a relatively low pressure, the product is mostly in the vapor phase when it reaches the manifold that is, the ammonia composition is about 90 percent vapor and 10 percent liquid ammonia on a volume basis.
From the meter regulator, the liquid and vapor phases pass through a connector pipe which communicates with the flow equalizer manifold. The manifold structure is a circular chamber having openings in the side wall of the chamber and a cone-shaped bottom. Flexible applicator hoses connect the chamber wall openings to the soil knives. Inside the chamber is an orifice sleeve which seats against the chamber wall. This sleeve has openings in it which are smaller than the openings in the chamber wall and the openings in the sleeve line up with those in the chamber wall.
Because the ammonia is a two-phase system when it enters the flow equalizer manifold, it does not distribute uniformly through the applicator hoses into the soil knives. The distribution problem is caused by a centrifuging effect, in which the liquid phase is thrown to the outside of the manifold chamber. As the liquid phase travels around the manifold chamber, therefore, most of the liquid is discharged through the first few openings that it crosses in the orifice ring and the chamber sidewall. At the same time, the vapor phase of the ammonia leaves the manifold through those openings which offer the least amount of resistance.
From a study of the problem described above, it was concluded that the liquid and vapor phases of the ammonia had to be homogenized inside the manifold to improve the distribution of the product to the soil knives. In the practice of the present invention, a much better distribution of the ammonia product is achieved by modifying the conventional flow equalizer manifold used for the field application of ammonia fertilizers.